QtSystems: Remove qt.branch for this repository's master branch

The CI will checkout the depedencies specified in the sync.profile
file.

Change-Id: I0b9919642947f3fb05ad31f80d4acf038ab9dea6
Reviewed-by: Liang Qi <liang.qi@digia.com>
QtFeedback: Remove qt.branch for this repository's master branch

The CI will checkout the depedencies specified in the sync.profile
file.

Change-Id: I27f6cc884aabd91f74191d75036cbba8be6575b4
Reviewed-by: Liang Qi <liang.qi@digia.com>